Beisht is a sea monster and the wife of Osial.
For reasons unknown, she did not participate in Osial's attack on Liyue Harbor, suggesting that she may have been elsewhere when he was released from his prison. However, she was soon made aware that he had been defeated by the Jade Chamber, prompting her to avenge her husband. Her presence had been noted by Beidou while the captain was sailing at sea, who then warned Ningguang of her presence. Ningguang decided to rebuild the Jade Chamber to lure Beisht out pre-emptively, knowing that she would not be able to stand the presence of the very building that had defeated her husband. Prior to the construction, Ningguang had Keqing and Ganyu oversee construction of variants of the Guizhong Ballista at Guyun Stone Forest, ordered a large amount of medical wound dressing from Bubu Pharmacy and had Qiqi evacuate any people at the seaside.
Once the Jade Chamber was completed with the Traveler and Shenhe's help, Beisht emerged in the ocean and prepared to attack, although she was severely injured by Ningguang and the ballistae's attacks. After her tsunami was foiled by Shenhe, she dove into the deep sea but was pursued by both the Traveler and Shenhe, managing to wound her even more and causing her to flee the area.
- "Beisht" is likely derived from a creature of Manx folklore, the Beisht Kione.